Remote control switch with condition responsive element



@Mh my 1967 .1. s. MACHADO 3,309,480

REMOTE CONTROL SWITCH WITH CONDITION RESPONSIVE ELEMENT Filed April 27, 1964 United States Patent O 3,309,480 REMOTE CONTROL SWITCH WITH CONDITION RESPONSIVE ELEMENT John S. Machado, Woburn, Mass., assignor to United Electric Controls Company, Watertown, Mass., a corporation of Massachusetts Filed Apr. 27, 1964, Ser. No. 362,704

11 Claims. (Cl. ZOO-140) This invention relates to a -device for controlling refrigeration in trailer trucks and has for its principal lobjects to provide a device operative to maintain the temperature within the refrigerating space, at any given time, at a predetermined level; to provide a device for effecting rapid restoration of the temperature to the predetermined level in the event that it falls more than a predetermined amount below or rises more than a predetermined amount above the predetermined level; to provide a device which enables adjustment from a remote point; and to provide a device which is comprised of readily available components, is relatively easy to manufacture, durable, eflicientand depen-dable. It is to be understood however that the device is useful for analogous purposes where it is desirable to maintain, register and/or correct a change of predetermined amount from a given condition. j

As herein illustrated, the device comprises, in combination, a plurality of switches, a plurality of switch-actuators, means mounting the switches vfor movement relative to the switch-actuators, a sensing device operative to effect relative movement of the switches and switch-actuators, and an adjustable element for preconditioning the relative position of the switches and switch-actuatorsfor operation of one of the switches at a predetermined condition, the switch-actuators of the other two switches being adjustable relative to the switches to effect their operation in response to relative movement of the switches and switch-actuators which is less than or greater than the predetermined movement. The switches and switch-actuators are mounted at the distal ends of arms, the latter being supported at their proximal ends for rotation about a common axis and movement relative to each other about that axis. The sensing device comprises a fluid pressure operable motor having a part engaged with the switch-supporting arm, operative to effect movement of the switch-supporting arm and the switches supported thereby relative to the switch-actuators. A capillary tube, having a .bulb at one end containing a volatile fluid, is connected to the motor for effecting displacement in response to a change in ambient conditions of temperature or pressure. A spindle, engaged with the arm supporting the switch-actuators, is adjustable to preset the relative position of the arms and has a 'graduated dial fixed thereto and a knob for effecting its rotation relative to a reference mark to establish a predetermined condition for operation. A fourth switch, supported adjacent the adjustable spindle, is operative, by a cam mounted on the spindle at a predetermined position, to disable operation of one of the three switches.

The device is used in conjunction with a heat pump for effecting refrigeration of a predetermined space, the pump 'being driven by a motor and being provided with a reversible valve. The centrally located switch is operably connected to the reversible valve to effect its reversal cyclically at the predetermined temperature selected by rotation of the dial relative to the reference mark. The remaining two switches are operably connected to the pump motor and are effective to increase its speed and hence the speed of rotation of the pump by displacement of the fluid pressure motora lesser or greater amount than the predetermined amount.

The invention will now be described in greater detail with reference to the accompanying drawings wherein:

FIG. 1 is a side elevation of the device, partly in section and partly broken away;

FIG. 2 is a front elevation, partly broken away;

FIG. 3 is a plan view;

FIG. 4 diagrammatically illustrates the use of the device for controlling a heat pump such as is used for refrigeration; and

FIG. 5 is a vertical section taken on the line 5-5 of FIG l.

Referring to the drawings, the device has a box-like enclosure 10 of substantially rectangular cross-section, having front and back walls 12 and 14, side walls 16--16 and top and bottom walls 18 and 20. The front, back and side walls are divided intermediate the bottom and top to provide a bottom part 22 and a top part 24, the latter being secured to the bottom part by four screw bolts 26 inserted through holes in the walls of the top part and extending downwardly through the holes into threaded holes in the walls of the bottom part.

A shaft 23 is fixed between the side walls 16-16 of the bottom part in a horizontal position adjacent the back wall 14 and pivotally supports a part 34) and a part 32 for movement relative to the axis of the shaft 28 and for movement relative to each otl'ier. The part 30 comprises a pair of transversely spaced arms 34-34 containing, at their proximal ends, openings 36-36 for receiving the shaft 28. The distal ends of the arms 34-34 contain spaced openings 38*38 for receiving bolts 40-40, the opposite ends of which are threaded for receiving nuts 42-42 at the outer sides of the arms. Three switches 44-1, 444 and 44-3, containing openings corresponding in spacing to the openings 38-38, are mounted between the arms 34-34 on the bolts 40-40, the latter passing through the openings in the switches so that the switches are pivotally movable in unison about the axis of the shaft 28. A U-shaped bearing plate 46 (FIG. 2) is mounted on the bolts 40-40 so as to underlie the bottom side of the center one of the switches 44-2.

These switches 44-1, 44-2 and 44-3 are of the kind commonly known as microswitches as disclosed in Patent No. 3,019,312, dated Jan. 30; 196'2.

The part 32 comprises va flat plate 48 having along its 'opposite sides right-angularly disposed, spaced parallel flanges Sti- 50. The rear ends of these flanges contain openings 52-52 for receiving the shaft `28 by means of which the part 32 is free to pivot about the axis of the shaft 28. The distal end of the plate 48 has at its upper side three bosses 54-1, 54-2v and 54-3, containing threaded openings 56-1, 56-2 and 561-3, the axes of which coincide with the axes of the actuating pins of the switches. Spindles 58-1, 58-2 and 58-3 are threaded into the openings 56-1, 56-2 and 56-3 respectively, so that their lower end-s are adjacent the actuating pins of the switches. The 'upper ends of the spindles 58-1 and 58-3 have hexagonal heads and are provided with slots -by means of which they may be rotated to adjust their heightwise position relative to the plate 48. The boss 54-2 is sealed at the top so that the spindle 58-2 is not accessible for adjustment. A coiled spring 60 is mounted on the spindle 58-2 with one end abutting the underside of the plate 48 and the other end abutting the top of the switch 44-2, and operates normally to hold the parts 30 and 32 separated so that pressure must be brought to bear to bring the spindles 58-1, 58-2 and 58-3 into engagement with the switch-actuating pins of the switches.

A hollow boss 62 (FIG. 1) is formed integral with the bottom wall 20 of the bottom part of the enclosure Within which there is mounted a uid pressure motor in the form of a bellows 64 having a fixed lower end and a movable upper end. A plunger 66 is fixed to the movable upper end and extends through an opening in the bottom wall 20 into a position immediately below the bearing plate 46 so as to have contact therewith. The fixed end of the bellows is connected to a capillary tube 68 of a length determined by the use of the device, having at its extremity a bulb 70 which contains a suitable temperatureresponsive uid. As herein illustrated, the bulb is in the form of a coil 70x of the tubing and may be placed in whatever position or place where a temperature is to be measured, recorded or maintained.

Expansion of the bellows 64 move-s the part 30 in a counterclockwise direction, as illustrated in FIG. 1, and contraction permits its movement in a clockwise direction.

The top rwall 18 of the enclosure has a centrally located opening 74 which is threaded for receiving a spindle 76, the lower end of which extends into the enclosure and has engagement with the top of the plate 48, the intermediate part of which is threaded at 77 for adjustment in the threaded opening 74 and the top part of which has secured to it a calibrated dial 78 and a knurled knob 80 by means of which it m-ay be turned. Lock nuts 82-82 are threaded onto the intermediate threaded portion 77 above and below the top wall 18 for xing the heightwise position of the spindle 76 relative to the part 32 when an adjustment is once made. A reference mark is provided adjacent an edge of the dial 78 in the form of a groove 82 made at the upper end of a nub 34 formed on the top wall 1S. Two openings 86-86 are formed through the top wall 18 vertically above the heads of the spindle 58-1 and 58-3 to permit an implement to be inserted through the top wall for adjusting the spindles.

A snap-action switch 88, similar to the switches referred to above, is fastened to the underside of the top wall 18 with its actuating pin opposite the spindle 76 and a cam 90 lis mounted on the spindle which is operative, by rotation of the spindle, to actuate this switch.

From the foregoing, it is evident that the spindle 76, by the engagement with the part 32, limits counterclockwise movement thereof so that expansion of the bellows 64 moves the part 30 relative to the part 32. This construction provides a convenient means for adjusting the device to operate at specic temperature levels which may be set by rotating the spindle 76 and dial 78 to position the desired indices thereon opposite the reference mark. Rotation of the spindle 76 to elevate it permits the part 32 to move away from the plunger 66 hence requiring a greater expansion of the bellows to effect actuation of the switches. Conversely, rotation of the spindle to move it toward the plunger 66 results in actuation of the switches at an earlier point in the expansion of the bellows.

A jack 92 is mounted in the bottom wall 20 and provides means for supplying the several switches with current.

A typical use of this device, but without limit to such use, is for controlling the temperature within refrigerated trailer trucks and for this purpose the bulb 70x is placed within the return air stream duct inside the trailer and the device itself in a convenient place for adjustment by the operator.

Referring to FIG. 4, the switch marked 44-2 is connected to -a solenoid 92 of a solenoid-operated valve V which is operable to reverse the direction of flow of refrigerant through a heat pump 94, the latter being driven by a motor M. Under ordinary conditions, with the motor running at 1200 r.p.m., the switch 44-2 will cycle the heat pump between low speed cool and low speed heat so as to maintain the temperature within the refrigerator substantially constant. The occurrence of unusual changes in external conditions may cause the system to overrun in one direction or the other so that the reversing of the cycle of operation, provided by switch 44-2, will not compensate rapidly enough to prevent damage either through excessive refrigeration or not enough refrigeration. Accordingly, the switches marked 44-1 land 44-3 are connected through solenoids 96-96 to the motor M to increase the speed of the motor M from 1200 to 2400 r.p.m. and hence the heat pump so that if the temperature is more than a predetermined amount below the selected temperature as indicated by the dial, or is more than a predetermined temperature above that selected temperature, the speed of the motor M will be increased so as to speed-up the cooling or the heating and to bring the temperature of the refrigerated space back to the selected temperature as quickly as possible. This is provided for by adjusting the spindles 58-1 and 58-2 relative to the switches 44-1 and 44-3 so that if the bellows 64 expands beyond a predetermined amount the switch 44-3 will be actuated and if it contracts beyond a predetermined amount the switch 44-1 will be actuated. For example, if the dial is set for 30 F. so that the -switch 44-2 will operate to maintain the system at a uniform temperature of 30, the switches 44-1 and 44-3 may be set by adjustment of the spindles S8-1 and 58-3 to operate, respectively, when the temperature falls more than 2 below 30 or rises more than 2 above 30.

The switch marked 88 is wired in series with the switch 44-1 to prevent the high-speed heating function from being accidentally initiated when the system is set below 20 F. This switch is operated independently of the temperature and is actuated -by means of the cam 90 on the spindle 76.

The foregoing device may be used for other purposes than controlling refrigeration. It may be employed in any situation where it is desirable to maintain a uniformly constant condition and to correct as rapidly as possible a change from the condition in either direction Ibeyond a predetermined amount. Moreover, while the sensing element 70, as herein shown, is responsive to a change in temperature, a pressure-responsive element may be substituted therefor where the control of pressure is desired instead of temperature. Optionally, the device may be employed simply to give a warning signal of change beyond a predetermined amount or to give a signal which will initiate some other compensating mechanism or circuit.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall Within the scope of the appended claims.

I claim:

1. A control device comprising .a support, a pair of arms pivotally mounted at one end on the support for movement about a common axis relative to the support and to each other, three switches mounted at the distal end of one arm, three actuators mounted at the distal end of the other arm, said switches and switch-actuators being engageable by relative movement of the arms, an adjustable spindle mounted on the support with an end engaging said other arm, sai-d spindle limiting its movement relative to its pivot, a sensing device including means engaged with said one arm, said means being movable in response to a change in ambient condition, to effect Imovement of said one arm relative to said other arm, means on the support for adjusting the position of the adjustable spindle to effec-t actuation of one of the switches in response to a predetermined response of the sensing device, and means on said other arm for Iadjusting the switch-actuators of the other two switches to effect their operation when the response is less than or greater than said predetermined response. y

2. A control device comprising a housing, a shaft mounted in the housing, a pair of arms pivotally supported on said yshaft at one end for movement relative to the shaft yand to each other about the axis of the shaft, three switches mounted a-t the distal end of one arm, Zhree switch-actuating pins mounted at the distal end of the other arm in a position such that relative movement of the arms will bring the pins into engagement with the switches, one of said pins being fixed and the other two -adjustable relative to said other arm, an adjustable spindle mounted on the support with one end protruding from the housing and the other end in engagement with the ar-m supporting the switch-actuating pins, a fluid pressure operable motor mounted on the housing, said motor embodying a plunger engaged with the arm supporting the switches, said plunger being movable to effect movement of the switch-supporting arm relative to the arm supporting the switch-actuating pins, said adjustable spindle being adjustable on the support, by rotation about its longitudinal axis, t-o position the arms relative to each other such that a predetermined movement of the plunger will bring the fixed pin into engagement with the switch opposed to it at a predetermined temperature, and said adjustable pins Ibeing adjustable on said other arm so that movement of said other -arm a predetermined lesser or greater amount will actuate one or the other of the other two switches, and a sensing element connected to said motor.

3. A device according t-o claim 2, wherein the adjustable spindle has a graduated dial tixed to its outwardly projecting end rotatable with the spindle relative to a reference mark on the housing adjacent the edge of the dial.

4. A device according to claim 2, wherein the Huid pressure operable motor is a bellows having fixed and movable ends, the plunger engaged with the switch-supporting arm is secured to the movable end, a capillary tube is connected to the ffixed end, Iand a bulb is formed at the distal end of the tube rfor holding a `volatile fluid.

5. A device according to claim 2, wherein a fourth switch is mounted on the housing adjacent the adjustable spindle disabling operation of one of the switches at a predetermined condition, and there is a cam on the spindle engageable, when the dial is rot-ated to sa1d predetermined condition by rotation of the spindle, to effect disabling of said switch.

6. A device according to claim 3, wherein there is means on the housing for locking the dial in a predetermined selected position.

7. Apparatus according to claim 2, wherein the housing is comprised of lower and upper par-ts, the lower part containing the switch-actuating supporting arm and the motor, and the upper part containing the adjustable spindle and fourth switch. v

8. A control device having top, bottom |and side walls arranged rectangularly, a shaf-t xed at its ends between one pair of side walls parallel to the others a pair of spaced parallel Iarms pivotally mounted iat one end on the shaft, three switches mounted between the -distal ends of the arms, bolts extending through the arms and the switches there'between supporting the switches between the ends of the arms, a plate having spaced parallel, rightangularly disposed flanges along its opposite edges, said flanges containing openings receiving the shaft, by means of which the plate is pivotally supported above the switchsupporting arms, for movement about the axis of the sha-ft relative to the switches, three -threaded bosses on 4the plate opposite the switches, a fixed pin mounted in the centrally located boss and an adjustable pin mounted in the boss at each side thereof, a spring disposed abou-t the fixed pin with one end abutting the underside of the plate and the other end abutting the top of the subjacent switch, a plunger situated adjacent the bottom of the housing beneath the switches with its upper end vadjacent said switch, said plunger moving the switches in unison upwardly relative to the plate supporting the switch-actuating pins, la bellows mounted on the housing having a movable end connected to the plunger and a fixed en-d to which is connected a capillary tube, an adjustable spindle mounted on the housing above the plate, a dial and knob on the outer end of the spindle, said spindle being rotatable to fix the position of the plate relative to the switches such that the centrally located switch will Ibe actuated at a predetermined temperature, graduations on the dial movable relative to a reference j mark on the housing, and lock nuts fixing the dial in a prede-termine-d adjust-able position, said adjustable pins being adjustable in said bosses to effect actuation of said other switches at a lesser or greater temperature than said predetermined temperature.

9. A control device operative to produce a sign-al within predetermined limits of operation and additional signals beyond said predetermined limits comprising means supporting a pair of arms for pivotal movement relative to each other about a common axis, switches and means securing the switches to one of t-he arms, switch-actuators and means mounting the switch-actuators on the other arm, said switch-actuators operating by relative movement of the arms, to Iactuate the switches, spring means situ-ated ybetween the arms yieldingly holding the actuators and switches separated, a fluid pressure operable motor embodying a part engaging the means securing the switches to the arm supporting the switches to move said switch-supporting arm toward the arm supporting the actuators, adjustable means engaging the arm supporting the actuators limiting the pivotal movement of the arm supporting the actuators, and means on the arms supporting the actuators for positioning the actuators on the actuator-supporting arm such that, between predetermined limits, one switch is actua-ted and the others are not and below and above said limits the other switches are operated.

10. A control device operative to produce a signal Within predetermined limits of operation and additional signals beyond said predetermined limits comprising means supporting a pair of arms for pivotal movement relative to each other about a common axis, switches mounted on one arm, switch-actuators mounted on the other arm, said switch-actuators operating, by relative movement of the arms, to actuate the switches, spring means situated -between the arms yieldingly holding the actuators and switches separated, a fluid pressure -operated motor operating the arm supporting the switches to move said switch-supporting arm toward the arm supporting the actuators, adjustable means engaging the arm supporting the actuators for limiting said pivotal movement of the actuator-supporting arm, one switch operating at said limiting position to produce a signal, and the other two switches operating, by relative movement of the switchsupporting arm, Ia different amount relative to the actuator-supporting arm at said limiting position to produce additional signals.

11. A control device opera-tive to produce a signal within predetermined limits of operation and additional signals beyond said predetermined limits comprising means supporting a pair of arms Ifor pivotal movement relative to each other about a common'axis, switches mounted on one arm, switch-actuators mounted on the 'other arm, said switch-actuators operating, by relative movement of the arms, to actuate the switches, spring means situated between the arms yieldingly holding the actuators and switches separated, a fluid pressure operated motor engaging the arm supporting the switches to effect movement of the arm supporting lthe switches, adjustable means engaging the arm supporting the actuators for limi-ting pivotal movement thereof, said switch-supporting arm being movable relative to the actuator arm a-t said limiting position of the actuator-supporting arm to actuate one of said switches, and operating, by movement rela-tive to said limi-ting posit-ion a, predetermined lesser.

amount or greater amount than said relative movement, to actuate one or the other `of the two remaining switches.

References Cited by the Examiner UNTED STATES PATENTS 8 Strysko ZOO-140 Noakes 200-140 Noakes 20D- 140 Lieberhann 62-160 Harnish 62--160 Kucera 20D-140 BERNARD A. GILHEANY, Primary Examiner.

G. MAIER. Assistant Examiner. 

1. A CONTROL DEVICE COMPRISING A SUPPORT, A PAIR OF ARMS PIVOTALLY MOUNTED AT ONE END ON THE SUPPORT FOR MOVEMENT ABOUT A COMMON AXIS RELATIVE TO THE SUPPORT AND TO EACH OTHER, THREE SWITCHES MOUNTED AT THE DISTAL END OF ONE ARM, THREE ACTUATORS MOUNTED AT THE DISTAL END OF THE OTHER ARM, SAID SWITCHES AND SWITCH-ACTUATORS BEING ENGAGEABLE BY RELATIVE MOVEMENT OF THE ARMS, AN ADJUSTABLE SPINDLE MOUNTED ON THE SUPPORT WITH AN END ENGAGING SAID OTHER ARM, SAID SPINDLE LIMITING ITS MOVEMENT RELATIVE TO ITS PIVOT, A SENSING DEVICE INCLUDING MEANS ENGAGED WITH SAID ONE ARM, SAID MEANS BEING MOVABLE IN RESPONSE TO A CHANGE IN AMBIENT CONDITION, TO EFFECT MOVEMENT OF SAID ONE ARM RELATIVE TO SAID OTHER ARM, MEANS ON THE SUPPORT FOR ADJUSTING THE POSITION OF THE ADJUSTABLE SPINDLE TO EFFECT ACTUATION OF ONE OF THE SWITCHES IN RESPONSE TO A PREDETERMINED RESPONSE OF THE SENSING DEVICE, AND MEANS ON SAID OTHER ARM FOR ADJUSTING THE SWITCH-ACTUATORS OF THE OTHER TWO SWITCHES TO EFFECT THEIR OPERATION WHEN THE RESPONSE IS LESS THAN OR GREATER THAN SAID PREDETERMINED RESPONSE. 